BJ70 A/C and Heat Dash Console Repair?

[futura22]

Hello all, has anyone had any experience in fixing the heat and cool air controls on a bj70 / 70 series? I am not even sure if the heater is working properly because of how jammed the setting knobs are on the dash. (You basically cant move them) Perhaps the wires are old and
Need oiling of some sort? Any help or advice is appreciated and thanks a lot

 

[JTarnow]

If you take the dash apart you can get to the cables that connects the controls to the heater. They get a little rusty on the exposed parts of the wire. Some fine steel wool and wd40 works well. The hardest one to get to is the temp control one that goes to the heater box inside the truck. Don't forget to get both ends of the cables.

 

[jericho]

The temp lever on my BJ74 had come apart and made it difficult to operate. I pulled the module and pieced it together with nut and bolt and some washers. There's a small plastic pin that gave way and couldn't keep the pieces together. Not sure if its the same problem.

 

[futura22]

Ok cool thanks for the info I will see what I can do !

 

[JuanJ]

Hello,

Once you are done, do not forget to coat the contacts with vaseline or bulb grease before plugging them back.





Juan

 

[Shes Mad]

If you take the dash apart you can get to the cables that connects the controls to the heater. They get a little rusty on the exposed parts of the wire. Some fine steel wool and wd40 works well. The hardest one to get to is the temp control one that goes to the heater box inside the truck. Don't forget to get both ends of the cables.

The heat control is on the bottom on the BJ70. If you take the bottom center vent off, you can move it by hand, to see if the cable is stuck. All the vents operate off of a short cable on the left side of the heater box, with complicated levers.

Both are pretty easy to take the cable end off . Not so easy to get the control end off. If you disconnect from the box, you will be able to tell if it is the control, cable or the box levers

 

[jasheehan]

just picked up a BJ70 and my temperature and select knob is stuck. I'm afraid to crank on it. Is there a flapper inside that controls the air flow to the different vents? Do any of you have any pics on where to begin to look into this. If the select and temp control knobs are stuck, any recommendation on where to start? Thanks.

 

[Felde]

The heat control goes to a fluid valve that is located on the firewall in the engine bay. Quit obvious. Just follow the hoses in the engine bay.
You can detach the control cable there and check the valve. There is a good chance it is blocked or seized and thus also blocking the mechanic.
Some WD40 on the valve mechanism may do a miracle.
When detached from the valve, the control cable should be movable with the leaver free and easy. If not, its the mechanism and the dash needs to come apart partially to follow the linkage.
I'm not aware of any mechanism to control the amount of heat other than by controling the amount of heated fluid by that valve.

Regarding the airflow:
Find the blower unit. Usually it is a pot-shaped thing in the passenger footwell. On top of it is a mesh with a (usually very ugly) foam material.
When operating the airflow leaver from 'outside fresh' to 'inside circulation', this mesh swings back and gives way for the inside air to directly flow into the blower, while at the same time blocking the channel to the outside air intake on its rear.
The amount of air is controlled only by the driving air pressure and blower speed. Airflow can be blocked by the flaps directly on each air vent, operated by the center knob in each vent. I'm not aware of any other flaps in the air channels. (A/C is a different story).
Regards
Ralf

 

[AndrewHadji]

i replaced the engine side valve as it had seized, used chain lube where i could, nice and smooth now.

 

[jasheehan]

Thanks. I'll get into this over the weekend and take a look. Are all these connections accessible or do you need 6' long skinny arms to get after them?

 

[Felde]

The heating valve is easy to access. The control cable path not too much as it goes trough the firewall and dash.
The removing the air blower as a whole is a PITA (at leat with my truck having A/C). You can get to it by removing the glove box (easy) and the air duct beyond it. Not that difficult to that stage.
What I would do again is: Try to detach the control cable from that mesh mechanic on the blower and check operation of the parts separately.
I never took out the control leaver assembly from the dash, so I can't help on that. Maybe the body repair manual tells how to do it.
Good luck!